Tire vulcanization mold and pneumatic tire

ABSTRACT

A tire vulcanization mold including a sector mold divided into a plurality of pieces along a circumferential direction of a green tire, the sector mold configured to vulcanization mold a tread portion of the green tire into a predetermined shape, and an upper mold and a lower mold disposed on both sides of the green tire so as to sandwich the green tire therebetween in an axial direction of the green tire, the upper mold and the lower mold configured to vulcanization mold a side portion of the green tire into a predetermined shape. The sector mold has a relief groove in a vicinity of a fitting portion between the sector mold, and the upper mold and the lower mold.

CROSS-REFERENCE TO RELATED APPLICATIONS

The application is a Divisional of U.S. patent application Ser. No.15/730,122, filed on Oct. 11, 2017, which claims priority of JapanesePatent Application No.: 2016-244692 filed on Dec. 16, 2016, the contentof which is incorporated herein by reference.

BACKGROUND OF THE INVENTION Technical Field

The present invention relates to a tire vulcanization mold and apneumatic tire.

Related art

In vulcanization molding of a pneumatic tire, two kinds of moldscorresponding to molded portions are generally used. One is a mold formolding a tread portion of the tire, which is called a sector mold. Theother is a mold for molding a sidewall portion over a shoulder portionof the tire, which is called a side mold. The sector mold is dividedinto a plurality of pieces and arranged in the circumferential directionof the tire, and the side mold is arranged so as to sandwich the tirefrom the side. The green tire (raw tire) is subjected to vulcanizationmolding in a state of being closed by these two kinds of molds, and apneumatic tire as a product is manufactured.

For example, JP 63-66206 U discloses a pneumatic tire molded by such asector mold and a side mold. In the pneumatic tire disclosed in JP63-66206 U, in order to prevent the rubber from being caught by a moldduring molding and to prevent the poor appearance of the tire, aprotrusion is provided at the bottom of the lug groove of the tire onthe side mold side.

SUMMARY

In the molding of the pneumatic tire disclosed in JP 63-66206 U, aprotrusion is provided at the bottom of the lug groove of the tire onthe side mold side. However, the position and shape of the protrusionhas not been studied in detail so as to suppress rubber from flowing tothe fitting portion of the molds. Therefore, there is still room forimprovement in the tire vulcanization mold disclosed in JP 63-66206 U.

An object of the present invention is to provide a tire vulcanizationmold capable of suppressing a pneumatic tire from representing a poorappearance which is caused by an event in which the rubber has beencaught during molding and a pneumatic tire in which such a poorappearance is suppressed.

The tire vulcanization mold of the present invention includes a sectormold divided into a plurality of pieces along the circumferentialdirection of a green tire, the sector mold configured to vulcanizationmold the tread portion of the green tire into a predetermined shape, anda pair of side molds disposed on respective sides of the green tire soas to sandwich the green tire therebetween in the axial direction of thegreen tire, for the side molds configured to vulcanization mold a sideportion of the green tire into a predetermined shape, wherein the sectormold has a recess in the vicinity of a fitting portion between thesector mold, and the side molds.

According to this configuration, when the mold is closed, the rubber ofthe tire can escape to the recess provided in the sector mold, so thatthe flow of the rubber to the fitting portion of the mold can besuppressed. Therefore, it is possible to suppress the rubber from beingcaught by the mold, and it is possible to suppress occurrence of thepoor appearance of the pneumatic tire. In particular, the recess isprovided in the sector mold instead of the side mold, thereby furthersuppressing the rubber from being caught. In detail, when the mold isclosed, normally the sector mold moves inward in the radial direction ofthe tire in a state where the side mold is fixed. Therefore, thepositional relationship between the side mold and the tire is fixed, andthe rubber of the tire flows toward the closing sector mold. Therefore,the recess is provided in the sector mold and the rubber escapes to therecess, thereby suppressing the rubber from being caught in the fittingportion.

The recess may have a depth of 0.3 mm or more and 0.5 mm or less.

According to this configuration, the depth of the recess is defined,thereby further suppressing the rubber from being caught, and ensuringthe releasability of the mold. Specifically, the depth of the recess is0.3 mm or more, whereby the rubber in an amount necessary forsuppressing the rubber from being caught can escape into the recess.Further, the depth of the recess is 0.5 mm or less, thereby preventingthe rubber from deeply entering the recess. Therefore, it is possible toprevent the rubber from becoming difficult to be released from the moldwhen the mold is opened, that is, it is possible to ensure releasabilityof the mold.

The recess may be provided away from the fitting portion by a distanceof 0.5 mm or more and 0.8 mm or less.

According to this configuration, the distance between the recess and thefitting portion is defined, thereby preventing durability of the moldfrom deteriorating and further suppressing the rubber from being caught.In detail, the recess is 0.5 mm or more away from the fitting portion,whereby the thickness of the sector mold in the vicinity of the fittingportion can be sufficiently ensured. Therefore, it is possible toprevent durability of the sector mold from deteriorating. Since thesector mold contacts the side mold at the fitting portion, and thesector mold is subjected to receive impact upon every molding, it isvery effective to be able to prevent durability in the vicinity of thefitting portion of the sector mold from deteriorating. In addition, therecess is provided within a distance of 0.8 mm from the fitting portion,whereby the flow of the rubber to the fitting portion can be suppressedmore reliably. If the recess is provided extremely far from the fittingportion, the recess does not affect the flow of the rubber toward thefitting portion, and the effect of suppressing the rubber from beingcaught at the fitting portion cannot be provided.

The sector mold may be provided with a projection for forming a luggroove on an outer circumferential surface of the green tire, and therecess may be provided away from the projection by a distance of 0.5 mmor more and 0.8 mm or less.

According to this configuration, the distance between the recess and theprojection is defined, thereby preventing durability of the tire to bemanufactured from deteriorating, and sufficiently ensuring an area forarranging the recess in the mold. In detail, the recess is 0.5 mm ormore away from the projection, thereby preventing a ridge line frombeing formed in the vicinity of the lug groove of the tire to bemanufactured. If the recess is provided extremely close to theprojection, a ridge line is formed in the vicinity of the lug groove inthe tire. In that case, since the lug groove and the ridge line form aprotruding and recessed relation, the abrasion rate of the tire isincreased. Therefore, by preventing the formation of the recessextremely close to the projection, it is possible to prevent theabrasion resistance of the tire from deteriorating, that is,deterioration of the durability of the pneumatic tire can be prevented.If the recess is provided extremely far from the projection, that is, ifthe recess is provided extremely close to the fitting portion, the areafor providing the recess between the fitting portion and the projectionis decreased. Therefore, the recess is provided within a distance of 0.8mm from the projection, whereby the sufficient area for arranging therecess in the mold can be ensured.

The recesses may be a plurality of grooves in a mesh shape extending ina direction intersecting with both a circumferential direction and aradial direction of the green tire. The recesses may be groovesextending annularly in a circumferential direction of the green tire.

According to this configuration, the recess is provided so as to extendin a direction intersecting with the flow direction of the rubber(radial direction of the tire) to the fitting portion. Therefore, whenthe rubber flows to the fitting portion, the rubber stretches across therecess, so that the rubber can reliably escape to the recess. Therefore,the flow of the rubber to the fitting portion can be suppressed, and itis possible to prevent the rubber from being caught. In particular, whenthe recess is provided in a mesh shape, the rubber can escape in variousdirections, and it is possible to more reliably suppress the rubber frombeing caught. Particularly, when the recess is provided in thecircumferential direction of the tire, since the recess can be formed bylathe machining or the like, it is easy to process the recess.

The pneumatic tire according to the present invention includes aprotrusion-shaped mold fitting mark located between a tread portion anda side portion, and a protrusion-shaped molding mark provided in thevicinity of and outside of the mold fitting mark.

According to this configuration, the pneumatic tire is manufacturedusing the mold having said recess, thereby suppressing the rubber frombeing caught. Thus, occurrence of poor appearance of the pneumatic tireis suppressed. Therefore, the aesthetic appearance of the tire ismaintained. Here, the vicinity of and the outside of the mold fittingmark refer to a range within, for example, 0.8 mm from the mold fittingmark on the radially outer side of the pneumatic tire.

According to the present invention, it is possible to suppress therubber from being caught during molding in the tire vulcanization mold,and it is possible to maintain the aesthetic appearance of the pneumatictire.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and the other features of the present invention willbecome apparent from the following description and drawings of anillustrative embodiment of the invention in which:

FIG. 1 is a partial sectional view of a vulcanization molding machineequipped with a tire vulcanization mold according to an embodiment ofthe present invention;

FIG. 2A is an enlarged view of a fitting portion of the tirevulcanization mold of FIG. 1;

FIG. 2B is a front view of a recess of FIG. 2A;

FIGS. 3A to 3F are partial sectional views showing a clamping operationof the tire vulcanization mold of FIG. 1;

FIG. 4 is a cross-sectional perspective view of a pneumatic tiremanufactured by the tire vulcanization mold of FIG. 1; and

FIG. 5 is a front view of a recess showing a modification from FIG. 2B.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described withreference to the accompanying drawings.

FIG. 1 shows a state in which a tire vulcanization mold 2 according tothe present embodiment is attached to a vulcanization molding machine 1.The tire vulcanization mold 2 is attached via a container 6 between anupper plate 3 and an upper platen 4 of the vulcanization molding machine1, and a lower platen 5.

The upper plate 3 is fixed to the lower end of a lifting cylinder 7. Alifting rod 8 is disposed at the center of the lifting cylinder 7. Theupper platen 4 is fixed to the lower end of the lifting rod 8. Thelifting cylinder 7 and the lifting rod 8 are moved up and down by adriving device (not shown). The upper plate 3 and the upper platen 4 areconfigured to be able to move up and down independently. A flow path 4 ais formed in the upper platen 4. The temperature can be adjusted by theflow of a heat exchange medium (for example, oil) in the flow path 4 a.

As with the upper platen 4, a flow path 5 a in which the heat exchangemedium flows is formed in the lower platen 5. Adjusting the temperatureof the heat exchange medium allows the tire vulcanization mold 2 to havea desired vulcanization temperature through the upper platen 4 and thelower platen 5. A bladder unit 9 is disposed at the center of the lowerplaten 5.

In the bladder unit 9, a bladder 13 is attached to an upper clamp 11 anda lower clamp 12 which are fixed to a vertically movable support shaft10. Air is supplied to and discharged from a space surrounded by theupper clamp 11, the lower clamp 12, and the bladder 13 by asupply/exhaust device (not shown). The bladder 13 is inflated toward itsouter circumference side by the supply of air, and supports a green tireGT from the inside. Here, the green tire GT indicates a raw tire beforebeing subjected to vulcanization molding.

A container 6 includes a segment 14, a jacket ring 15, an uppercontainer plate 16, and a lower container plate 17.

The segment 14 is screwed to a sector mold 20 of the tire vulcanizationmold 2 described later at each of respective pieces. In the presentembodiment, the segment 14 is consisted of nine pieces, and the sectormold 20 is also consisted of nine pieces. The inner surface of thesegment 14 is disposed along the outer surface of the sector mold 20,and its outer surface is constituted by an inclined surface (outerperipheral conical surface) gradually expanding toward the outerdiameter side in going downward. The segment 14 is reciprocablysupported in the radial direction by an upper slide 18.

A jacket ring 15 has a hollow cylindrical shape. The upper end surfaceof the jacket ring 15 is fixed to the upper plate 3, and the jacket ring15 moves up and down according to the lifting action of the liftingcylinder 7. The inner surface of the jacket ring 15 is constituted by aninner peripheral conical surface inclined toward the outer diameter sideso as to gradually enlarge its diameter in going toward the lower end ofthe jacket ring 15. The inner peripheral conical surface of the jacketring 15 and the outer peripheral conical surface of the segment 14 slidealong the conical surface so as not to be away from each other (forexample, by a configuration like a tenon and a dovetail groove). As aresult, when the jacket ring 15 descends, the outer peripheral conicalsurface of the segment 14 is pressed by the inner peripheral conicalsurface of the jacket ring 15, and it is possible to move the segment 14expanding toward the outer diameter side into a state in which thepieces of the segment 14 are annularly continuously disposed on theinner diameter side.

The upper slide 18 is fixed to the undersurface of the upper containerplate 16 on the outer peripheral side thereof, and an upper mold 21,which will be described later, is fixed to the undersurface of the uppercontainer plate 16 on the inner peripheral side thereof. The uppercontainer plate 16 itself is fixed to the undersurface of the upperplaten 4. As a result, when the lifting rod 8 moves up and down, theupper mold 21 and the segment 14 (including the sector mold 20 fixed tothe segment 14) move up and down together with the upper platen 4 andthe upper container plate 16.

The lower slide 19 is fixed to the top surface of the lower containerplate 17 on the outer peripheral side thereof, and a lower mold 22,which will be described later, is fixed to the top surface of the lowercontainer plate 17 on the inner peripheral side thereof. On the lowerslide 19, the segment 14 is placed at the time of mold clamping and issupported slidably in the radial direction. The lower container plate 17itself is fixed to the top surface of the lower platen 5.

The tire vulcanization mold 2 includes the sector mold 20, the uppermold (side mold) 21, and the lower mold (side mold) 22.

The sector mold 20 is a mold for vulcanization molding the tread portionof the tire into a predetermined shape. The sector mold 20 is made of analuminum alloy and is divided into a plurality of pieces in thecircumferential direction of the tire (nine divisions in this case), andthe pieces are continuously disposed in a ring shape in a state wherethe pieces are moved to the inner diameter side.

FIG. 2A is an enlarged view of a portion surrounded by a circle C inFIG. 1, that is, FIG. 2A is an enlarged view of a fitting portionbetween the sector mold 20 and the upper mold 21 (or the lower mold 22).In FIG. 1, there are two portions surrounded by a circle C. Since eachenlarged view of the two portions differs only in orientation and isidentical in shape, the two portions are shown in FIG. 2A by one figure.Hereinafter, the term “fitting portion” refers to a fitting portionbetween the sector mold 20 and the upper mold 21 (or the lower mold 22).The fitting portion has a recessed shape and has a shape like an openbeak. This recessed shape can suppress the rubber from being caught inthe fitting portion when the mold is closed. The sector mold 20 isprovided with a projection 20 a for forming a lug groove on the tiresurface in order to improve driveability of the tire to be manufacturedand a relief groove (recess) 20 b for suppressing the rubber from beingcaught.

The relief groove 20 b is provided at a position, for example, 0.5 mmaway from the fitting portion (W1=0.5 mm) and is provided at a position,for example, 0.5 mm away from the projection 20 a (W2=0.5 mm). Aplurality of relief grooves 20 b is provided, and in this embodiment,three relief grooves 20 b are provided. The relief groove 20 b has, forexample, an R portion having a radius of about 1.0 mm with respect tothe surface of the sector mold 20. The interval between the reliefgrooves 20 b is, for example, about 1.0 mm (W3=1.0 mm). As also shown inFIG. 2B seen from the direction of the arrow A in FIG. 2A, the reliefgroove 20 b of the present embodiment extends in the circumferentialdirection of the tire, and the sectional shape thereof is a triangularshape. The depth of the relief groove is, for example, about 0.4 mm(D=0.4 mm). In FIG. 2B, in order to clearly show the position of therelief groove 20 b, marking is schematically indicated by oblique lineswith respect to the relief groove 20 b.

The relief groove 20 b has a preferable range of position and shape. Therelief groove 20 b is preferably provided at a position 0.5 mm to 0.8 mmaway from the fitting portion, that is, the width W1 preferablysatisfies 0.5 mm≤W1≤0.8 mm. Further, the relief groove 20 b ispreferably provided at a position 0.5 mm to 0.8 mm away from theprojection 20 a, that is, the width W2 preferably satisfies 0.5mm≤W2≤0.8 mm. The interval between the relief grooves 20 b is preferably0.7 mm to 1.3 mm, that is, the width W3 preferably satisfies 0.7mm≤W3≤1.3 mm. Further, the depth of the relief groove 20 b is preferably0.3 mm to 0.5 mm, that is, the depth D is preferably 0.3 mm≤D≤0.5 mm.While the cross-sectional shape of the relief groove 20 b is preferablya triangular shape, it may be any shape, such as a semicircular shape ora trapezoidal shape, for example. The significance of the preferablerange of the position and the shape of the relief groove 20 b will bedescribed later.

As shown in FIG. 1, the upper mold 21 and the lower mold 22 are moldsfor vulcanization molding the side portions of the tire into apredetermined shape.

The upper mold 21 is formed in an annular shape, and an upper bead ring23 is fixed to the inner periphery of the upper mold 21. The upper mold21 is fixed to the upper container plate 16, and moves up and down asthe lifting rod 8 moves up and down. When the upper mold 21 descends,the upper bead ring 23 can hold down the bead portion of the green tireGT. Thereby, a sidewall portion and a bead portion of the tire areformed by the lower inner surface of the upper mold 21 and theundersurface of the upper bead ring 23.

As with the upper mold 21, the lower mold 22 is formed in an annularshape, and a lower bead ring 24 is fixed to the inner peripheral portionof the lower mold 22.

FIGS. 3A to 3F are partial cross-sectional views showing the moldclamping operation of the tire vulcanization mold 2 of the presentembodiment. In the present embodiment, the green tire GT is set in thevulcanization molding machine 1 equipped with the tire vulcanizationmold 2 having the above-described configuration. After closing the mold,and the mold is clamped, the vulcanization molding of the green tire GTis performed.

In the mold open state shown in FIG. 3A, the green tire GT is placed onthe lower mold 22 so that the axial direction of the green tire GTdirects upward and downward. At this time, the bead portion of the greentire GT on the lower side is aligned with the lower bead ring 24.

As shown in FIG. 3B, air is then supplied into the bladder 13 to inflatethe bladder 13 and hold the inner surface of the green tire GT on theouter surface of the bladder 13. As a result, the green tire GT issupported by the lower bead ring 24 and the bladder 13, and is in anon-contact state with the lower mold 22.

As shown in FIG. 3C, the upper mold 21 and the sector mold 20 aresubsequently lowered by the lifting rod 8 and the lifting cylinder 7.Then, the upper bead ring 23 comes into contact with the bead portionpositioned at the upper side of the green tire GT.

As shown in FIGS. 3D and 3E, subsequently, after the green tire GT ispressed and deformed via the bead portion, the upper mold 21 comes intocontact with the green tire GT. When the upper mold 21 descends to themold clamping completion position, the green tire GT is sandwichedbetween the upper mold 21 and the lower mold 22.

As shown in FIG. 3F, the descent by the lifting cylinder 7 is continuedeven after the upper mold 21 has descended to the mold clampingcompletion position, and the jacket ring 15 is downwardly moved togetherwith the upper plate 3. As a result, the inner peripheral conicalsurface of the jacket ring 15 presses the outer peripheral conicalsurface of the segment 14. Then, the sector mold 20 fixed to the segment14 moves toward the inner diameter side.

The vulcanization molding is performed after the mold clamping iscompleted as shown in FIGS. 3A to 3F. After completion of the molding,when the tire vulcanization mold 2 is opened by the reverse motion, thegreen tire GT becomes a pneumatic tire as a product.

FIG. 4 shows the pneumatic tire AT manufactured as described above. Thepneumatic tire AT includes an annular and linear mold fitting mark 30formed by a fitting portion between the sector mold 20 and the uppermold 21 (or the lower mold 22), and a protrusion-shaped relief groovemark (molding mark) 31 provided in the vicinity of and the outside ofthe mold fitting mark 30. Here, the vicinity of and the outside of themold fitting mark 30 refer to a range within, for example, 0.8 mm fromthe mold fitting mark 30 on the radially outer side of the pneumatictire AT. The relief groove mark 31 is provided between the mold fittingmark 30 and the lug groove 32 in the radial direction of the pneumatictire AT. In FIG. 4, three streaks of relief groove marks 31 are showncorresponding to the number of the relief grooves 20 b in FIG. 2B. Thenumber of the relief groove marks 31 to be formed is the same as thenumber of the relief grooves 20 b. In addition, the relief groove mark31 has a cross-sectional shape corresponding to that of the reliefgroove 20 b. Therefore, for example, the relief groove mark 31 formedfrom the relief groove 20 b with the triangular cross section of thisembodiment have a chevron cross-sectional shape. In this way, the reliefgroove mark 31 is formed corresponding to the relief groove 20 b withrespect to dimensions, positions, etc. in addition to thecross-sectional shape.

According to the present embodiment, when the tire vulcanization mold 2is closed, the rubber of the tire can escape to the relief groove 20 bprovided in the sector mold 20. Thus, it is possible to suppress therubber from flowing to the fitting portion of the tire vulcanizationmold 2. Therefore, it is possible to suppress the rubber from beingcaught by the tire vulcanization mold 2 and the poor appearance of thepneumatic tire can be prevented. Particularly, the recess 20 b isprovided in the sector mold 20 instead of the upper mold 21 (or thelower mold 22), thereby further suppressing the rubber from beingcaught. In detail, when the tire vulcanization mold 2 is closed asdescribed above, the sector mold 20 moves inward in the radial directionof the tire while the upper mold 21 (or the lower mold 22) is fixed.Since the positional relationship between the upper mold 21 (or thelower mold 22) and the tire is fixed, the rubber of the tire flowstoward the closing sector mold 20. Therefore, the recess 20 b isprovided in the sector mold 20, and the rubber escapes to the recess 20b, thereby suppressing the rubber from being caught in the fittingportion.

The depth of the relief groove 20 b is defined, thereby preventing therubber from being caught, and ensuring releasability of the tirevulcanization mold 2. Specifically, the relief groove 20 b has a depthof 0.3 mm or more, whereby the rubber in an amount necessary forsuppressing the rubber from being caught can escape. Further, the reliefgroove 20 b has a depth of 0.5 mm or less, thereby preventing the rubberfrom deeply entering into the relief groove 20 b and becoming difficultto be released from the tire vulcanization mold 2 when the mold 2 isopened.

The distance W1 between the relief groove 20 b and the fitting portionis defined, thereby preventing durability of the tire vulcanization mold2 from deteriorating, and the rubber from being caught. In detail, therelief groove 20 b is 0.5 mm or more away from the fitting portion,whereby a sufficient thickness of the sector mold 20 in the vicinity ofthe fitting portion can be ensured. Therefore, it is possible to preventdurability of the sector mold 20 from deteriorating. Since the sectormold 20 comes into contact with the side molds 21, 22 at the fittingportion, and the sector mold is subjected to receive impact upon everymolding, it is very effective to be able to prevent durability of thesector mold 20 in the vicinity of the fitting portion fromdeteriorating. In addition, the relief groove 20 b is provided within adistance of 0.8 mm from the fitting portion, thereby more reliablysuppressing the rubber from flowing to the fitting portion. If therelief groove 20 b is provided extremely far from the fitting portion,the flow of the rubber toward the fitting portion cannot be suppressed,and it is impossible to provide the effect of preventing rubber frombeing caught in the fitting portion.

Further, the distance W2 between the relief groove 20 b and theprojection 20 a is defined, thereby preventing durability of the tire tobe manufactured from deteriorating, and sufficiently ensuring the areafor arranging the relief groove 20 b. Specifically, the relief groove 20b is 0.5 mm or more away from the projection 20 a, thereby preventing aridge line from being formed in the vicinity of the lug groove of thetire to be manufactured. If the relief groove 20 b is provided extremelyclose to the projection 20 a, the ridge line is formed in the vicinityof the lug groove in the tire. In that case, since the lug groove andthe ridge line form a protruding and recessed relation, the abrasionrate of the tire is increased. Therefore, by preventing the formation ofthe relief groove 20 b extremely close to the projection 20 a, it ispossible to prevent the abrasion resistance of the tire fromdeteriorating, that is, deterioration of durability of the pneumatictire can be prevented. If the relief groove 20 b is provided extremelyfar from the projection 20 a, that is, if the relief groove 20 b isprovided extremely close to the fitting portion, the area for providingthe relief groove 20 b between the fitting portion and the projection 20a is decreased. Therefore, the relief groove 20 b is provided within adistance of 0.8 mm from the projection 20 a, whereby the sufficient areafor arranging the relief groove 20 b in the mold can be ensured.

Further, a relief groove 20 b is provided so as to extend in a direction(circumferential direction of the tire) intersecting with the flowdirection of the rubber (radial direction of the tire) to the fittingportion. Therefore, when the rubber flows into the fitting portion, itstretches across the relief groove 20 b, so that the rubber can reliablyescape to the relief groove 20 b. Therefore, the flow of the rubber tothe fitting portion can be suppressed, and it is possible to prevent therubber from being caught. In particular, when the relief groove 20 b isprovided in the circumferential direction of the tire, it is easy toprocess the relief groove 20 b.

As described above, in the pneumatic tire AT (see FIG. 4), since thebiting of rubber during molding is suppressed, occurrence of poorappearance of the pneumatic tire AT is suppressed. Therefore, theaesthetic appearance of the tire is maintained.

FIG. 5 shows a modification corresponding to FIG. 2B of the aboveembodiment. A plurality of relief grooves 20 b of this modificationextend in a direction intersecting with both the circumferentialdirection and the radial direction of the green tire GT, that is, therelief grooves 20 b are provided in a mesh shape. The relief grooves 20b of the present modification extend so as to intersect with each of thecircumferential direction and the radial direction at an angle of 45degrees. The relief grooves 20 b may intersect with each of thecircumferential direction and the radial direction at an angle otherthan 45 degrees.

According to the present modification, when the relief groove 20 b isprovided in a mesh shape (including a knurl shape), the rubber canescape in various directions, and it is possible to more reliablysuppress the rubber from being caught.

The form of the relief groove 20 b is not limited to parallel streaksextending along the circumferential direction of the tire shown in FIG.2B and a mesh shape which intersects with both the circumferentialdirection and the radial direction of the tire shown in FIG. 4. Forexample, the form of the relief groove 20 b may be parallel streakswhich intersect with the radial direction of the tire.

Although the specific embodiments of the present invention and itsmodifications have been described above, the present invention is notlimited to the above-described embodiments, and various modificationscan be made within the scope of the present invention. For example, anappropriate combination of descriptions of individual embodiments may beone embodiment of the present invention.

What is claimed is:
 1. A pneumatic tire comprising: a protrusion-shapedmold fitting mark located between a tread portion and a side portion;and a protrusion-shaped molding mark provided in a vicinity of andoutside on the mold fitting mark, wherein the molding mark is aplurality of protrusions in a mesh shape extending in a directionintersecting with both a circumferential direction and a radialdirection.
 2. The pneumatic tire according to claim 1, wherein themolding mark has a height of 0.3 mm or more and 0.5 mm or less.
 3. Thepneumatic tire according to claim 1, wherein the molding mark isprovided away from the mold fitting mark by a distance of 0.5 mm or moreand 0.8 mm or less.
 4. The pneumatic tire according to claim 2, whereinthe molding mark is provided away from the mold fitting mark by adistance of 0.5 mm or more and 0.8 mm or less.
 5. The pneumatic tireaccording to claim 1, wherein a lug groove is provided on an outersurface of the pneumatic tire, and wherein the molding mark is providedaway from the lug by a distance of 0.5 mm or more and 0.8 mm or less. 6.The pneumatic tire according to claim 2, wherein a lug groove isprovided on an outer surface of the pneumatic tire, and wherein themolding mark is provided away from the lug by a distance of 0.5 mm ormore and 0.8 mm or less.
 7. The pneumatic tire according to claim 3,wherein a lug groove is provided on an outer surface of the pneumatictire, and wherein the molding mark is provided away from the lug by adistance of 0.5 mm or more and 0.8 mm or less.
 8. The pneumatic tireaccording to claim 4, wherein a lug groove is provided on an outersurface of the pneumatic tire, and wherein the molding mark is providedaway from the lug by a distance of 0.5 mm or more and 0.8 mm or less. 9.A pneumatic tire comprising: a protrusion-shaped mold fitting marklocated between a tread portion and a side portion; and aprotrusion-shaped molding mark provided in a vicinity of and outside onthe molding mark, wherein the molding mark is provided away from themold fitting mark by a distance of 0.5 mm or more and 0.8 mm or less,and wherein the molding mark is a protrusion extending annually in atire circumferential direction.